Crystal Structure and Solution Structural Dynamic Feature of 1,8-Dibenzoyl-2,7-Dimethoxynaphthalene

The crystal structure and the dynamic feature of molecular structure in solution for 1,8-dibenzoyl-2,7-dimethoxynaph-thalene are revealed by X-ray crystallographic analysis and VT-NMR measurements. In crystal, the molecule of the title compound is located on a twofold rotation axis. The two benzoyl groups are situated in an opposite direction. The dihedral angle between the mean planes of the phenyl ring and the naphthalene ring system is 80.25(6). The benzene ring and carbonyl moiety in each benzoyl group are almost coplanar. The molecular packing is stabilized by weak C–H…O hydrogen bonds and aπ-πstacking interaction between the benzene rings [centroid-centroid and interplanar distances of 3.6383(10) and 3.294 , respectively]. In solution, the temperature-dependent rotation behavior of the C–C bond between the benzene ring and the ketonic carbonyl group has been observed by1H VT-NMR measurements. Furthermore, comparison of the C–C bond rotation behavior between the benzene ring and the carbonyl group with 1-ben-zoyl-2,7-dimethoxynaphthalene has clarified that the C–C bond between the ketonic carbonyl group and the naphthalene ring rotates slower than the 1,8-dibenzoylated homologue.

Microstructure and corrosion mechanism of as-cast Mg-Zn-Mn-Ca in Hank's solution

An Mg-Zn-Mn-Ca alloy with high Zn content was fabricated by vacuum melting.The as-cast microstructure was investigated using XRD,SEM and EDS.It was shown that the alloy was composed of α-Mg,strip-like Ca2Mg6Zn3 and a few Mncontaining phases.Most of the Ca2Mg6Zn3 phase was distributed at grain boundaries while Mn-containing particles were deposited within grains.The as-cast samples were immersed in a Hank's balanced salt solution(HBSS) up to 24 h.The corroded surface morphology and cross-section microstructure were analyzed after different time of immersion so as to understand the corrosion behavior of the alloy.During immersion in the HBSS,the alloy corroded homogeneously at the very beginning and then localized corrosion occurred.The secondary phases protruded on the surface due to the dissolution of α-Mg,suggesting microgalvanic corrosion occurred with secondary phases acting as the cathode and α-Mg as the anode.Micro-cracks were formed at the interfaces between Ca2Mg6Zn3 and α-Mg,indicating an undermining tendency of the secondary phases.

Effect of solid solution modification on structure and properties of dicalcium silicate

In the paper, dicalcium silicate (C2S) was modified to obtain higher performance, and the solutionizing pattern of BaSO4 in cement clinker was analyzed theoretically. According to experimental results, solutionizing of BaSO4in cement clinker improved crystal plane distance of C2S as well as the relations of coordination. The performance tests show that the strength of C2S modified by BaSO4 changes and the reactivity of C2S increases significantly.

Structural Probing on the Sn-C(C5 ring)Bond of the Sn(Ⅱ)Metallocenes in Both the Solid State and the Temperature-dependent Solution Relaxation State

Various bond modes of the M-C（C5 ring） exist in metallocene compounds of group 14 heavier elements,mostly due to an intricate interaction between the lone electron pairs at the M center and the 6 p-electrons of the C5 ring.The tin（Ⅱ） metallocene complexes LSn R（L = HC[CMe（N-2,6-iPr2C6H3）]2,R = cyclopentadienyl,C5H5（1）; indenyl,C9H7（2）; fluorenyl,C（13）H9（3）） stabilized by the β-diketiminato ligand were prepared and utilized in the study on their solid and solution state structures.X-ray single-crystal diffraction data revealed an η~1-mode of the Sn-C（C5 ring） bond in each 1~3.However,the room temperature ~1H NMR spectral studies disclosed such a fluxional bonding mode in solution.The 119 Sn NMR studies suggested a quadruple coordination nature of the Sn center in 1 while the triple coordination manner was for the Sn atom in both 2 and 3.Then the variable-temperature（25~–75 ℃） ~1H NMR spectral studies for each 1~3 were performed,which detected the relaxation state structures of 1~3 at lower temperature.All of these results indicate a stereochemical activity of the lone electron pairs at the tin（Ⅱ） atom that definitely has an electronic interaction with the 6 p-electrons of the C5 ring.The observed Sn-C（C5 ring） bond modes appear influenced by either the metallocene size or the compound state existed.

Structure and Bonding of Nanolayered Ternary Phosphides

We have studied the electronic structure and chemical bonding mechanism of nanolayered M2SbP with M = Ti, Zr and Hf using the full-relativistic of an all-electron full potential linearized augmented-plane-wave (FP-LAPW) method based on the density functional theory, within the local density approximation scheme for the exchange-correlation potential. Furthermore, we have to calculate the energy of formation for prove the existence of these compounds experimentally. Geometrical optimizations of the unit cell are in good agreement with the available theoretical and experimental data. The bulk modulus of M2SbP conserved as Ti is replaced with Zr, and increases by 8.7% as Ti is replaced with Hf, which can be understood on the basis of the increased number of valence electrons filling the p-d hybridized bonding states. The bonding is of covalentionic nature with the presence of metallic character. Analyzing the bonding in the binary MP, it can be concluded that this character is essentially conserved in M2SbP ternaries.

Structure and Properties of Gel-spun Ultra-high Molecular Weight Polyethylene Fibers with High Gel Solution Concentration

The gel-spun ultra-high molecular weight polyethylene （UHMWPE） fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultimate structure and mechanical properties of UHMWPE fibers for different gel solution concentrations were analyzed by tensile testing, differential scanning calorimetry （DSC）, wide angle X-ray diffraction （WAXD） and small angle X-ray scattering （SAXS）. With the increase of gel solution concentration, the ultimate mechanical properties of UHMWPE fibers were decreased and the crystallization and orientation of UHMWPE fibers became inferior. Besides, both the average shish length （ （Lshsh） ） and shish misorientation （B0） of UHMWPE fibers were decreased with the increase of gel solution concentration. In addition, the appropriate increase of spinning temperature led to the further optimization of the ultimate structure and mechanical properties of UHMWPE fibers.

Facile and green route to highly luminescent ZnS-shelled CdSe nanocrystals

Highly luminescent CdSe/ZnS nanocrystals were obtained by adapting non-TOP-based synthesis and a subsequent two-phase ZnS shelling procedure:the core CdSe nanocrystals were synthesized in sole solvent paraffin liquid with cadmium oxide,elemental sele-nium,and oleic acid; the deposition of the ZnS shell was conducted by using zinc stearate in toluene and sodium sulfide in deionized water. The green and low-cost route was proved to be more efficient to constrain the size of core nanocrystals while tuning the ...

Growth and Characterization of New Non Linear Optical Bis-Glycine Hydro Bromide (BGHB) Single Crystal

A new non linear optical material, Bis-Glycine Hydro bromide (BGHB), has been synthesized. Single crystals of BGHB have been grown successfully by slow evaporation method. The solubility of the material was measured in various solvents such as ethanol, acetone and water. It was found to have extremely low solubility in ethanol and acetone. The grown crystals were characterized by recording the powder diffraction and identifying the diffracting planes. Using single crystal diffractometer the morphology of BGHB crystal was identified. Fourier transform infrared (FTIR) spectroscopic studies, optical behavior such as UV-visible-NIR absorption, Thermogravimetic (TG) and differential scanning calorimetric (DSC) analyses have been performed to show that BGHB is thermally stable up to 168.5℃ and there is no phase transition and decomposition till 168.5℃. Anisotropy in the hardness behavior has been observed while measuring at different crystal planes by Vicker hardness test.

玉米淀粉含量测定影响因素分析

【目的】研究不同检测方法对玉米直链淀粉和支链淀粉含量测定结果的影响,为玉米淀粉含量检测提供理论依据。【方法】采用双波长分光光度计测定不同玉米中直链淀粉、支链淀粉含量,比较不同玉米中淀粉溶液参比波长、吸光度和吸光谱,并利用扫描电镜观察淀粉颗粒结构,研究影响玉米淀粉含量测定的因素。【结果】高直链玉米、普通玉米和糯玉米中直链淀粉淀粉含量分别为64.8%、25%和1.9%,支链淀粉含量分别为32.3%、75.6%和97.1%。乙酸和盐酸处理后,3种玉米淀粉溶液pH值均降低,其中乙酸对高直链玉米淀粉溶液pH值影响最大。【结论】盐酸处理后3种淀粉溶液吸光度值以及吸收峰值均高于乙酸处理的吸光度值,并且直链淀粉吸光度及吸光谱高于支链淀粉。普通玉米淀粉颗粒膨大,表面凹凸不平,呈不规则形状,高直链玉米淀粉颗粒结构改变虽有变化,但没有普通玉米剧烈。直链淀粉水溶液没有支链淀粉水溶液稳定。

外磁场及硫酸镁对碳酸钙溶解行为的影响机理研究

为揭示动态水条件下外磁场中硫酸镁对碳酸钙溶解过程的影响规律,采用SEM、XRD、离子浓度检测、电导率检测等手段对碳酸钙的溶解行为进行表征,结果表明:外磁场及硫酸镁可明显提升碳酸钙的溶解能力,当外磁场中硫酸镁的质量分数由0升至3.0%时,溶液中钙离子浓度升高了58.62%;外磁场可使碳酸钙(104)晶面间距、微观应变和位错密度增大,使得碳酸钙的晶胞体积膨胀、结构疏松,晶体缺陷增多,有利于碳酸钙与水分子的水合及其在水溶液中的溶解扩散,硫酸镁则通过镁离子的盐效应促进溶液中碳酸钙的溶解。研究成果可为采用磁化技术调控碳酸钙溶解行为研究提供参考。

Discontinuous solid solutions of anthracene-phenanthrene:Thermodynamics and crystallization kinetics

We explored such issues as the formation mechanism,structure and propriety of the solid solutions of anthracene(ANT)-phenanthrene(PHE).Solution crystallization and solid-state grinding were employed to prepare solid solutions under different conditions.The thermal behavior and PXRD scanning results revealed the formation of discontinuous solid solutions,whose melting points and crystal lattices varied linearly with mixed ratio.Combing with Materials Studio,the formation possibility of solid solutions were investigated by evaluating the change of the energy.The crystal morphology of the solid solutions have a positive correlation with the change of the major part.Finally,the solution crystallization process of solid solution were studied using the population balance model.

一水硬铝石型铝土矿铝硅浮选分离溶液化学 Ⅰ—晶体结构与可浮性

系统分析了我国铝土矿中含硅脉石矿物高岭石、伊利石、叶蜡石的晶体结构与表面性质 ,讨论了晶体结构与铝硅酸盐矿物表面断裂键的特性、润湿性、电性及可浮性的关系 ,以及晶格杂质与可磨性对浮选行为的影响。结果表明三种矿物晶体边面上晶面的单位面积断裂键数皆有如下关系 :NSi-O( 110 ) <NSi-O( 0 10 ) <NSi-O( 10 0 ) ,NAl-O( 110 ) <NAl-O( 0 10 ) <NAl-O( 10 0 ) ,它从理论上解释了高岭石、叶蜡石和伊利石三种矿物晶体边面上润湿性的各向异性 ,一水硬铝石及铝硅酸盐矿物晶体结构的差异 ,使表面断裂的Al—O、Si—O键及表面离子活性区存在差别 。

魔芋葡甘聚糖结构的研究进展

阐述国内外在魔芋葡甘聚糖一级结构、高级结构、晶体结构和溶液构象方面的研究进展,指出结构研究中存在的问题,并提出今后的研究方向。

实时研究KDP和DKDP晶体生长边界层的分子结构

When the crystal grows from solution,a sharp variated fluid layer of the solute concentration exists against crystal surface.The sharp variated fluid layer is defined the boundary layer in crystal growth.The molecular structure of the boundary layers plays a key role in crystal composition,morphology,growth rate and crystal growth mechanism.However,owing to the lacking of suitable probe technique,it is difficult to obtain the information of the moving construction of the boundary layers.Here,the laser Raman Microprobe combining with holographic phase contrast interferometric microphotography is used to probe in situ the molecular structure of the boundary layers during the crystal growth processes of KH 2PO 4(KDP) and KD 2PO 4(DKDP).In supersaturations ranging from 1% to 14%,Raman scattering states at the different positions within the boundary layers have been investigated,and compared with the bands of different concentration solutions alone using laser Raman spectroscopy between 600 and 1350cm -1 .The changes in band parameters of the phosphates within the boundary layers of crystal growth are different from those in solution alone.The influence of the solution concentration on the band parameters of anion phosphate within the layers is nonlinear.With increasing supersaturation,the full width at half height of the P=O 2 symmetric stretch band increases.The new 918(938)cm -1 H(D)O P OH(D) asymmetric stretch,1120(DKDP 1200)cm -1 O P O asymmetric stretch,and extremely weak 1210cm -1 P O H in plane deformation bands appear in the characteristic boundary layers.These new bands show that the cations have direct effects on the phosphate group(aggregates).Under the driving of concentration gradient field of supersaturation,the effects of cations cause the changes of O P O bond angle,atomic charge redistribution,and lead to readjust geometry of anion phosphate group and desolvation.The trend of readjust is close to the geometry of the crystal structure unit and the formation of the cations phosphate crystallization unit.

非线性光学晶体BaBPO_5的生长、结构研究

本文采用顶部籽晶高温溶液法 ,以Li4P2 O7为助熔剂 ,生长了大尺寸BaBPO5单晶。进行了BaBPO5晶体的结构测定 ,结果表明该晶体属三方晶系 ,空间群 :P32 2 1,晶胞参数为a =b =0 .7132 9(10 )nm ,c =0 .70 36 8(14 )nm ,α =β =90° ,γ =12 0°,Z =3。该晶体结构中沿 [0 0 1]方向存在BO4四面体链 ,每一个硼氧四面体用它的两个顶点分别与两个PO4四面体相连组成螺旋状的链。硼氧四面体、磷氧四面体和钡氧多面体结合在一起形成一个三维网络结构。同时 ,对BaBPO5的粉末倍频效应进行了研究。

Ti^(4+)固溶堇青石的制备、结构和红外辐射性能的研究

采用固相反应法制备了名义组成为Mg2(1-x)Ti2xAl4(1+x)Si(5-4x)O18(x=0、0.1)的堇青石体系红外辐射材料, 采用XRD、IR、29Si MAS NMR等方法研究了材料的结构,并考查了 Ti4+固溶及合成温度对材料红外辐射性能的影响。研究结果表明样品中形成以α 堇青石为主体的晶体结构。Ti4+ 的固溶使 T1(与[MgO6]八面体一起在六元环之间起连接作用的四面体)和T2(组成六元环结构的四面体)四面体上 Al、Si分布的有序度提高, 引起α 堇青石晶格畸变,增强了晶格振动的非简谐效应,从而提高了样品的红外辐射性能。合成温度的提高有利于 Ti4+ 固溶堇青石的充分形成和红外辐射性能的改善。合成温度为1420℃时,样品的法向全波段的辐射率达到 0.89,在 8~14μm波段范围内的辐射率达到0.90~0.94。

晶体生长溶液、熔体结构与生长基元

根据喇曼光谱、红外光谱测试了晶体生长的水溶液、溶剂和熔体的结构 ,并且在水热条件下进行了外加直流电场的实验 ,证实了晶体生长基元为负离子配位多面体 ,在不同的温度和溶液浓度条件下 ,负离子配位多面体相互联结成不同结构形式和不同维度的生长基元 (聚集体 ) ,不同维度的生长基元往晶体各个面族上的叠合速率是各不相同的 ,表现在同一种晶体在不同的生长条件下 ,其结晶形态可以各不相同 ,由此进一步阐述了负离子配位多面体生长基元理论模型的合理性。

固溶时效对超高氮奥氏体不锈钢析出行为的影响

用金相法、电镜观察等研究固溶+时效处理过程中超高氮奥氏体不锈钢氮化物及金属间相析出行为。结果表明:在超高氮奥氏体不锈钢中,随850℃等温时间的延长Cr2N析出过程为:沿晶界链条状析出→沿三晶界交汇处胞状析出并伴随少量的晶内析出→逐渐向晶内生长并与晶内析出相连呈层片状布满整个晶面,Cr2N的析出形态多以颗粒状、蠕虫状、层片状、菊花状分布;随着氮化物的析出伴随有σ相析出,这些金属间相多呈片状出现。探讨了各析出物的析出机理;通过析出物形貌TEM观察和选区衍射分析(SAD)确定了氮化物晶体结构及其与基体的位向关系;氮主要是以Cr2N和过饱和间隙原子的形式存在。

氟氯磷灰石固溶体晶体性质的密度泛函理论研究

基于密度泛函理论(DFT)研究了氟磷灰石、氯磷灰石及不同Cl含量的氟氯磷灰石固溶体晶体结构和电子性质。结果表明,随着Cl含量增加,体系能量趋于增大,同时晶体结构中a,b值呈增大趋势,c值却逐渐变小。态密度分析显示,Cl取代F后,Cl3s态较F 2s态向右移动,且在价带顶部Cl 3p态更靠近费米能级,同时峰费米能级附近Ca_23d态也更活跃。电荷分析显示Cl取代F后,主要电荷转移发生在通道原子F、Cl以及金属Ca;Mulliken键布居显示Ca_2—Cl较Ca_2—F键布居值更大且键长更长,其中在氯磷灰石中Ca_2—Cl键长达到了0.2608 nm。

非线性光学材料4氨基二苯甲酮晶体研究

本文报道了4氨基二苯甲酮(ABP)晶体的结构参数,描述了晶体的形貌与轴向,确定结晶轴与折射率主轴的关系。用溶液降温法已从丙酮、乙醇溶液中生长出透明单晶。测定了ABP 晶体的透过光谱,讨论了 ABP 晶体中对非线性效应起主要贡献的基团结构因素。